Lamp making machine and oven therefor



July 31, 1956 a. E. OTT

LAMP MAKING MACHINE AND OVEN THEREFOR 2 Sheets-Sheet 1 Filed April 1.1953 II I 0 5 H & \L 3 0 6 L f I 6 //T/ O 2 I 5 v% n J o 9 4 Yo 2 3 Ill\ /7 x 4 M/ lnvenoor; George E. 01st,,

(1 His Att, ney

July 31, 1956 Filed April 1, 1953 G. E. OTT

LAMP MAKING MACHINE AND OVEN THEREFOR 2 Sheets-Sheet 2 Inventor.- GeorgeE. 011/0, Y WC His Attorney LAMP MAKING MACHINE AND OVEN THEREFOR GeorgeE. Ott, Willoughby, Ohio, assignor to General Electric Company, acorporation of New York Application April 1, 1953, Serial No. 346,190

Claims. (Cl. 2637) My invention relates to automatic machines formanufacturing electric lamps and discharge devices. More particularly,my invention relates to an indexing form of an automatic machine havingin combination therewith an oven for heating lamps and discharge devicesat a succession of work stations.

The indexing type of machine, which advances the article to bemanufactured to each of a succession of work stations in turn is widelyused for the manufacture of lamps and discharge devices because of theease with which various manufacturing mechanisms and devices can beincorporated therein and because of the rapidity with which suchapparatus is capable of operating. When such machines have heatingapparatus in combination therewith, as for instance when it is requiredto heat the lamps or discharge devices in the course of exhausting themor to condition a coating on the envelopes of said lamps or dischargedevices, the proper control and distribution of heat is difficult toachieve except by the common types of radiant electric heatingapparatus.

One object of my invention is to reduce the cost of heating lamps anddischarge devices in the indexing or carrier type machine by providingin association therewith an oven in which air is heated by a burnerusing either gas or fuel oil, and in which the heated air is circulatedthrough the oven at certain of the work stations thereabout.

Another object of my invention is to provide such an oven so constructedand arranged as to heat relatively long tubular lamps and similardevices uniformly and speedily to a relatively high temperature. I havefound that the vertically disposed lamps are heated much more uniformlyby directing the heated air stream horizontally, rather than vertically,across the lamps.

Another object of my invention is to provide an air circulating type ofoven at a succession of work stations about a work carrying turret of amachine for making lamps and discharge devices, which is so constructedas to circulate the heated air horizontally in a manner to preventappreciable loss of heated air at the entrance and exit openings thereinso as to eliminate the need for doors at said openings.

Another object is to provide a novel structure wherein the roof andsidewalls of the oven are suspended from the top so that any expansionis in a downward direction whereby shoeplate members, carried by themachine heads and which seal the top of the oven, are always in contactwith their track.

Other objects and features of my invention will appear from thefollowing detailed description of a species thereof and from thedrawings.

In the drawings,

Fig. 1 is a plan view of approximately one half of an exhaust machinefor fluorescent lamps, said view being modified by the breaking away oftop sections of said machine including a series of lamp holding headsand the top of the oven.

Fig. 2 is a diagrammatic perspective view. showing essential elements ofthe oven.

Fig. 3 is a vertical section through a peripheral portion of the exhaustmachine and the adjacent oven portion nited States Patent O 2,756,980Patented July 31, 1956 along a vertical plane indicated by the dot-dashline 3--3 in Fig. 1.

In general, the oven illustrated in the drawings comprises an interiorheating area or chamber C into which projects a burner 25 and itsheat-distributing tube or muflle 24. The muflie is designed to spreadthe heat from the burner evenly from top to bottom of the heatingchamber C. This is an important feature in attaining uniformity intemperature of the air stream; it is not attained by a blower (such asshown at 28) alone. On one side of the chamber C is' a blower 28 mountedapproximately midway relative to the over-all height of the oven andwith its intake or suction side 42 projecting into the chamber C. Theblower 28 picks up the heated air and projects it into a distributingduct 29 at a high velocity, for example 9000 cubic feet per minute. Theduct 29, by virtue of its shape and the use of adjustable vanes 43, isdesigned to spread the heated air vertically so it will cover the entireheight of the oven. At the end of the duct 29 the air stream is made toturn approximately by means of a suitable bafiie 44. Adjacent this turnthere is located the exit opening 11 for passage of the lamps 4 from theoven. The construction is such as to cause the heated air to pass acrossthe exit 11 at a high speed and form an air curtain to prevent theescape of heat. The heated stream of air then continues to flow througha channel 8 contra to the movement of the lamps around the machine forthe desired distance after which it is again caused to turn 120 acrossthe entrance opening 5 and back into the heating chamber C where it isreheated and recirculated through the oven. In order to further assureagainst escape of heat from the entrance opening 5, I preferably providea second air curtain across that opening by means of a vertical pipe 35which is supplied with low pressure air, say 3.5 pounds per square inch,and which has a series of small holes arranged to provide the aircurtain. This construction eliminates the necessity of providing doorsacross the entrance and exit openings.

The oven is located to span a succession of work stations about amachine for exhausting elongated tubular lamps and conditioning acoating of fluorescent material on the inner surface thereof. The ovenis arranged below lamp carrying heads 1 of the exhaust machine, whichheads are regularly spaced about the periphery of a turret 2 on a centercolumn 3. The exhaust machine may be of the type shown in the UnitedStates Patent 2,247,513, Marshaus, dated July 1, 1941, which patent isassigned to the assignee of the present invention, and which providesfor certain operations in the manufacture of fluorescent lamps to takeplace, during the course of which said heads 1 are indexed in acounter-clockwise direction about the machine by movements of the turretor carrier 2. An elongated tubular fluorescent lamp 4 is retained in avertical position below each head 1 and is carried into the opening 5 inthe end of the oven while almost all of the head 1 remains above saidoven and maintains a connection to the said lamp 4 through meansextending through a slit 7 (Fig. 3) in the top of said oven 6. Thenormal indexing motions of the turret 2 advance the lamp 4 through thelength of the arcuate passageway 8 formed by the vertical outer wall 9and the inner thin metallic wall 10 of the oven 6 while the head 1 isadvanced to a succession of work stations of the machine. The lamp 4passes from the oven through opening 11 at the end of the passageway 8therein.

Each lamp 4 is connected to a head 1 by an exhaust tube 12 extendingupward from the lamp into the compression rubber 13 of the exhaustsystem, and is supported by the gripping action of jaws 14, 15 and 16 inengagement with an upper portion of the tubular envelope 17 thereof. Thejaws 14, 15 and 16 are mounted upon stationary and movable rods 18 and19 extending downward from the main portion of the head 1 represented bythe body 20 which also supports the exhaust rubber i3, and are arrangedin this particular instance to precede the lamp 4 as it enters theopening in the oven 6. At that time, the metal shoeplate 21 inassociation with the head 1 also slides onto the track rails 22 on thetop of the oven 6 and closes off the slit 7 therebetween accommodatingthe exhaust tube 12 and the rods 18 and 19.

The entrance of the lamps 4* into the passageway a; in the oven 6immediately subjects them to the heated air constantly being circulatedtherethrough and very soon thereafter advances the lamps into the mainair stream flowing in a clockwise direction about the machine andtherefore contra to the direction of movement of the lamps. The flow ofthe heated air at the end of the passageway 8 adjacent the opening 5 inthe oven 6 is sharply diverted laterally around the end of the innerwall it? thereof and along the outer wall 23 of the heating chamber. Thecontinued circulation of the air stream carries it into wiping relationto the cylindrical chamber or mufiie 24 which is located in an uprightposition at a point spaced from the entrance opening 5 at the end of theoven 6. While in contact with the muffle 24 the air stream is heated bythe gas flame directed into the open upper end thereof through theorifice block 25 of a burner mounted on the top 26 of the oven. The airstream also picks up the burning gases emerging from the openings 27 inthe opposite side of the rnuflle from that impinged upon by said airstream. The arrangement of openings 27 in the muflle assists inproviding the proper heat distribution therealong so that the air streamis heated quite uniformly by the time it is withdrawn from about thespace around the muffle 24.

The heated air is pulled from about the muffle 24 by the blower 23 whichdirects it through the duct 29 which in turn spreads it vertically tothe full height of the passage 8 of the oven 6 and causes it to enterthe passageway 8 therein at a point adjacent the exit opening 11. Thecentrifugal type blower 28, which is operated by an electric motor (notshown) through the belts 3t) extending from the pulley 31 on the blowershaft 32, is the source of motion for the air circulation system whichprovides for the heated air to pass through the passage 6 and then berecirculated through a close circuit including the heating chamber C,said blower 28 and the duct 29. The closed air circulation. systemprovides for the air about the cooler lamps 4 adjacent the entranceopening 5 to be drawn from the passageway 8 to the heating chamber C forreheating, at the same time heated ir from about the muffle 24 is forcedinto the opposite end of the passage 6 adjacent the opening 11.Vertically extending deflectors 33 and 34 are mounted upon the end ofthe wall 9 of the oven to cause the air stream to be deflected away fromthe opening 5 so that little air escapes therefrom.

Inasmuch as any loss of heated air from the opening is objectionablebecause of the resulting discomfort to operators of the machine, meansare provided for defleeting the heated air by jets of air directedacross said opening 5 from the low pressure air manifold 35. One set ofopenings 36 along the length of the manifold 35 directs jets of air intothe opening 5 at a very oblique angle so that an area of greater thanatmospheric pressure is developed at the mouth of the opening 5 whereasa second set of openings 37 along said manifold 35 directs jets of airacross said mouth of said opening 5 so that heated air passing beyondthe opening 5 is blown behind the shield 38 and directed away from theadjacent portion of the exhaust machine.

The cylindrical tube or muffle 24 is mounted in an upright position uponlegs resting upon the bottom 39 of the oven and is heated by the flamesintroduced into the upper end by a burner in part represented by theblock 25 (Fig. 3) in the roof of the oven and directing said flames downagainst the closed bottom 49 of the muffle. In certain instances wherethe temperature of the circulated air must be so high as to normallycause the muffle 24 to deteriorate rapidly, said muffle can be protectedby providing a relatively thick layer of a refractory cement over itsinside surface.

A low wall 41 of fire brick is also provided between the oven wall 10and the adjacent face of the blower 28 to cause the air emerging fromthe lower portion of the passage 6 to circulate up to heating relationwith the muffle 24 before entering the intake opening 42 of said blower28.

Since it is desirable that the lamps 4 be heated both as rapidly anduniformly as possible a high rate of circulation of the air is preferredand consequently a hig capacity blower 28 is provided. The blower 28,which is shown in a machine combination suited to the manufacture of thecommon forty-watt four-foot-long fluorescent lamps, draws the heated airfrom around the furnace 24 at the rate of 9,000 cu. ft. per min. and isof a construction to permit it to operate with air at 650 to 900 degreeC. The blower 28 is completely enclosed, except for the drive shaft 32,within the heavily insulated walls of the oven and is arranged slightlyabove the vertical center of the oven 6 so that it tends toautomatically direct more air in the top of the oven 6 as is required toheat the jaws 14, 15 and 16 of the lamp holding means. The heated airdischarged by the blower 28 passes into the small end of thedistribution duct 2) which is also completely contained within the wallsof the oven, and, in the course of its movement therethrough, isdirected suitably over the full vertical extent of the opposite end ofthe duct 29 by means of adjustable deflectors 43. The end of the duct 29spreads to the full height of the passage 8 and directs the heated airinto a curved pocket 4 in the end of the oven 6 in such a manner as tocause it to sweep into the passageway t; contra to the movement of thelamps 4 therein. This manner of directing the heated air into thepassage 8 reduces the air pressure at the opening 11 to substantiallyatmospheric pressure so that little heated air is lost to the atmospherethrough said opening 11.

A contributing factor to the proper pressure of the air within thepassageway 8 and, of course, the escape of air from the oven 6generally, is the flue 45 at the top of the end of the duct 29 in thatsaid flue 45 draws olf suflicient air to cause the oven 6 to bemaintained at or slightly below atmospheric pressure. The due 45 alsoserves to permit the products of combustion of the burning gasesintroduced into the air stream by the burner 25 to escape. A movement ofhot air at a rate of 200 ft. per min. passes through the length of thepassage 8 in the example outlined above with the result that the lamps 4are brought up to the elevated temperature of the air in less than halftheir travel through the said passage and are maintained at theirelevated temperature of said hot air for the remainder of the travel.

The high temperature of the air within the oven 6 requires that specialmeans be provided to insulate pro vide for the expansion of the variousparts thereof. As shown, the insulation 46 is comprised of relativelylarge sheets of expanded mica rock bound together with a suitable hinderor any of the well known products for this purpose. In every instancethe insulation 4-6 is attached to a sheet metal outer skin and ismounted in sections in the same manner as said skin. The top 26 andsides 23, 47 and 48 of the oven are bound together in a single unit bymeans of outwardly extending flanges 49 which are bolted together andare supported by a frame 59 (only partially shown) of angle iron inengagement with the top 26. Support is provided this assembly by legs 51attached only to the frame 50 and extending downward at spaced relationto the sides of the heating .apparatus so as to be out of the heat ofthe air stream and said sides. This manner of support causes allexpansion of the heating apparatus in a vertical direction to bedownward and maintains the top of the oven at essentially the samerelation to the heads 1 of the exhaust machine at all times.

The side 9 of the oven under the turret 2 is also mounted in essentiallythe same manner by means of angle pieces 52 welded to top portionsthereof and bolted to projections 53 on support brackets 54 on thestationary frame 55 of said exhaust machine. Other angle pieces 56attached to lower portions of the side'9 of the oven are slidable alongthe shanks of bolts 57 attached to other projections 58 on said brackets54 and hold said side 9 in its proper horizontal position while allowingit to expand freely in a vertical direction.

The bottom 39 of the oven, on the other hand, is independently mountedupon the blocks 59 carried by the bed plate 60 of the exhaust machineand other blocks (not shown) resting on the floor (also not shown).Because of the manner of mounting the bottom 39 of the oven, said bottom39 does not follow the expansion of the sides 9, 23, 47 and 48 and aslip joint like'that shown at 61 is provided at the junctiontherebetween to prevent leakage of air at said junction. A similar slipjoint comprised of a U-shaped strip 62 attached to the bottom 39 andengaging the lower edge of the entirely metal wall holds the lower endof said wall 10 in place.

While I have described the preferred embodiment of my invention, I donot wish to be limited to the exact structure shown as it will beunderstood that many modifications of the precise manner by which myinvention is carried into effect, as well as the apparatus in which itis used, may be made without departing from the scope of the appendedclaims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. The combination with a machine of the class described comprising acarrier having thereon a series of heads for holding lamps and advancingthem along a horizontal path of movement, of an oven located along saidpath and having therein vertical walls defining a horizontal passagewaytherethrough vertically aligned with the path of movement of said headsand having vertically extending openings at the horizontally oppositeends of said passageway to accommodate said lamps, said oven including aheating chamber adjacent and in communication with one verticallyextending end of said passageway and means to heat air substantiallyuniformly within said chamber, a blower having its intake sidecommunicating with said heating chamber, and a duct leading from theoutlet side of said blower to the other vertically extending end of saidpassageway to connect said blower, duct, passageway and heating chamberin a closed circuit within the oven for horizontal flow of heated airthrough said passageway.

2. The combination with a machine of the class described comprising acarrier having thereon a series of heads for'holding lamps and advancingthem along a horizontal path of movement, of an oven located along saidpath and having therein vertical walls defining a horizontal passagewaytherethrough vertically aligned with the path of movement of said headsand having vertically extending openings at the horizontally oppositeends of said passageway to accommodate said lamps, said oven including aheating chamber adjacent and in communication with one verticallyextending end of said passageway and means to heat air substantiallyuniformly within said chamber and comprising a vertically disposedtubular mufile member and a burner arranged to direct a flame into anend of said mufiie member, a blower having its intake side communicatingwith said heating chamber, and a duct leading from the outlet side ofsaid blower to the other vertically extending 6 end of said passagewayto connect said blower, duct, passageway and heating chamber in a closedcircuit within the oven for horizontal flow of heated air through saidpassageway.

3. The combination with a machine of the class described comprising acarrier having thereon a series of heads for holding lamps and advancingthem along a horizontal path of movement, of an oven located along saidpath, and having therein vertical walls defining a horizontal passagewaytherethrough vertically aligned with the path of movement of said headsand having vertically extending openings at the horizontally oppositeends of said passageway to accommodate said lamps, said oven including aheating chamber adjacent and in communication with one verticallyextending end of said passageway and means to heat air substantiallyuniformly within said chamber and comprising a vertically disposedtubular mufile member closed at its bottom and having openings along theside thereof facing away from the said one end of said passageway and aburner in the roof of the oven arranged to direct a flame downward intothe open upper end of said muffle member, a blower having its intakeside communicating with said heating chamber, and a duct leading fromthe outlet side of said blower to the other vertically extending end ofsaid passageway to connect said blower, duct, passageway and heatingchamber in a closed circuit within the oven for horizontal flow ofheated air through said passageway.

4. The combination with a machine of the class described comprising acarrier having thereon a series of heads for holding lamps and advancingthem along a horizontal path of movement, of an oven located along saidpath and having therein vertical walls defining a horizontal passagewaytherethrough vertically aligned with the path of movement of said headsand having vertically extending openings at the horizontally oppositeends of said passageway to accommodate said lamps, said oven including aheating chamber adjacent and in communication with one verticallyextending end of said passageway and means to heat air substantiallyuniformly within said chamber, a blower having its intake sidecommunicating with said heating chamber, and a duct leading from theoutlet side of said blower to the other vertically extending end of saidpassageway to connect said blower, duct, passageway and heating chamberin a closed circuit within the oven for horizontal flow of heated airthrough said passageway, and a flue in said duct at a point adjacent itsjunction with the said other end of said passageway.

5. The combination with a machine of the class described comprising acarrier having thereon a series of heads for holding lamps and advancingthem along a horizontal path of movement, of an oven located along saidpath and having therein vertical walls defining a horizontal passagewaytherethrough vertically aligned with the path of movement of said headsand having vertically extending openings at the horizontally oppositeends of said passageway to accommodate said lamps, said oven including aheating chamber adjacent and in communication with one verticallyextending end of said passageway and means to heat air substantiallyuniformly within said chamber, a blower having its intake sidecommunicating with said heating chamber, and a duct leading from theoutlet side of said blower to the other vertically extending end of saidpassageway at an acute angle thereto to connect said blower, duct,passageway and heating chamber in a closed circuit within the oven forhorizontal flow of heated air through said passageway, and meansdefining a concave pocket at the far end of said duct arranged tosharply divert the flow of air from said duct into said passageway andacross the adjacent opening at a high speed to form an air curtainacross said opening and prevent substantial escape of heated air therefrom. I

6. The combination with a machine of the class described comprising acarrier having thereon a series of heads for holding lamps and advancingthem along a horizontal path of movement, of an oven located along saidpath and having therein vertical walls defining a horizontal passagewaytherethrough vertically aligned with the path of movement of said headsand having vertically extending openings at the horizontally oppositeends of said passageway to accommodate said lamps, said oven including aheating chamber adjacent and in communication with one verticallyextending end of said passageway and means to heat air substantiallyuniformly within said chamber, a blower having its intake sidecommunicating with said heating chamber, and a duct leading from theoutlet side of said blower to the other vertically extending end of saidpassageway at an acute angle thereto to connect said blower, duct,passageway and heating chamber in a closed circuit within the oven forhorizontal flow of heated air through said passagewa and means defininga concave pocket at the far end of said duct arranged to sharply divertthe flow of air from said duct into said passageway and across theadjacent opening at a hi h speed to form an air curtain across saidopening and prevent substantial escape of heated air therefrom, anddeflector members in the said one end of said passageway adjacent thesaid opening thereat and arranged to deflect the air across said openingto minimize escape of heated air therefrom.

7. The combination with a machine of the class described comprising acarrier having thereon a series of heads for holding elongated tubularlamps vertically depending therefrom and for advancing them along ahorizontal path of movement, of an oven including side walls and a roofand a floor with means defining a horizontal passageway therethroughvertically aligned with the path of movement of said heads and havingvertically extending openings at the horizontally opposite ends of saidpassageway to accommodate said lamps, said oven including therewithin aheating chamber in communication with one vertically extending end ofsaid passageway and means to heat air substantially uniformly withinsaid chamber, a blower having its intake side communicating with saidheating chamber, a duct leading from the outlet side of said blower tothe other vertically extending end of said passageway to connect saidblower, duct, passageway and heating chamber in a closed circuit withinthe oven for horizontal flow of heated air through said passageway, theroof of said oven having a slit therein co-extensive with the saidpassageway therethrough to accommodate portions of said heads, shoeplatemeans on said heads in sliding engagement with the walls of said slit toseal it off, and support means suspending the roof and side walls of theoven from its top independently of its floor to thereby confineexpansion of the oven to a downward direction and maintain the sealbetween said shocplate means and the walls of said slit,

8. The combination with a machine of the class described comprising acarrier having thereon a series of heads for holding elongated tubularlamps vertically depending therefrom and for advancing them along ahorizontal path of movement, of an oven including side walls and a roofand a floor with means defining a horizontal passageway therethroughvertically aligned with the path of movement of said heads and havingvertically extending openings at the horizontally opposite ends of saidpassageway to accommodate said lamps, the roof of said oven having aslit therein co-extensive with the said passageway therethrough toaccommodate portions of said heads, shoeplate means on said heads insliding engagement with the walls of said slit to seal it off, andsupport means suspending th roof and side walls of the oven from its topindependently of its floor to thereby confine expansion of the oven to adownward direction and maintain the seal between said shoeplate meansand the walls of said slit.

9. The combination with a machine of the class described comprising aturret having at the periphery thereof a series of heads for holdingelongated tubular lamps vertically depending therefrom and for advancingthem along an arcuate path of movement, of an oven including sid wallsand a roof and a floor, one of said side walls being arcuate andco-extensive with a portion of the said path of movement of the lamps, asupplementary arcuate wall member of sheet metal located within saidoven concentric with said arcuate side wall and spaced therefrom todefine therebetween a horizontal passageway enclosing said portion ofthe said path of movement of the lamps, said supplementary wall memberextending vertically to the roof and floor of the oven but terminatingshort of the side walls thereof to leave vertically extending endopenings at the horizontally opposite ends of said passageway, said ovenhaving vertically extending entrance and exit openings adjacent the endsof the said arcuate side wall and in alignment with said passageway toaccommodate the said lamps, a heating chamber in said oven behind saidsupplementary wall and adjacent the end thereof contiguous to saidentrance opening, means to heat air within said chamber, a blower havingits intake side communicating with said heating chamber, and a ductleading from the outlet side of said blower to the end of saidpassageway adjacent said exit opening and at an acute angle thereto toconnect said blower, duct, passageway and chamber in a closed circuitfor horizontal flow of heated air through said passage in a directioncontra to the movement of the lamps therethrough.

10. The combination with a machine of the class described comprising aturret having at the periphery thereof a series of heads for holdingelongated tubular lamps vertically depending therefrom and for advancingthem along an arcuate path of movement, of an oven including side wallsand a roof and a floor, one of said side walls being arcuate andcoextensive with a portion of the said path of movement of the lamps, asupplementary arcuate wall member of sheet metal located within saidoven concentric with said arcuate side wall and spaced therefrom todefine therebetween a horizontal passageway enclosing said portion ofthe said path of movement of the lamps, said supplementary wall memberextending vertically to the roof and floor of the oven but terminatingshort of the side walls thereof to leave vertically extending endopenings at the horizontally opposite ends of said passageway, said ovenhaving vertically extending entrance and exit openings adjacent the endsof the said arcuate side wall and in alignment with said passageway toaccommodate the said lamps, a heating chamber in said oven behind saidsupplementary wall and adjacent the end thereof contiguous to saidentrance opening, means to heat air within said chamber, a blower havingits intake side communicating with said heating chamber, and a ductleading from the outlet side of said blower to the end of saidpassageway adjacent said exit opening and at an acute angle thereto toconnect said blower, duct, passageway and chamber in a closed circuitfor horizontal flow of heated air through said passage in a directioncontra to the movement of the lamps therethrough, means defining aconcave pocket at the far end of said duct arranged to sharply divertthe flow of air from said duct into said passageway and across theadjacent exit opening at a high speed to form an air curtain across saidopening, and deflector members in the end of said passageway adjacentthe entrance opening and arranged to deflect the air stream across saidentrance opening toward said heating chamber.

References Cited in the file of this patent UNITED STATES PATENTS884,427 Standish Apr. 14, 1903 99,513 Morrison Apr. 30, 1935 5,7 6Fulton et al. Nov. 20, 1951

